Research And Development Of Quality Monitoring System For Clinch Joint Based On Mechanical Deformation

Clinching based on mechanical deformation is a new technology of joining automotive metal sheets. It has a good prospect as it can effectively solve technological problems when using weld to join thin sheets and new material sheets. The quality monitoring system of clinching which can monitor joining process on line and discover errors in time during the process has great meaning of ensuring joining quality, protecting clinched tools without damage and improving the qualified rate of product. At present, quality monitoring systems of clinching are totally occupied by foreigner brands; domestic research in this area is still in the blank. This paper commencing from reality, combined with existing research results, introducing embedded technology, designed a quality monitoring system of clinching with intellectual property right.This paper first introduced forming principle, quality parameters, failure mode and quality detection of clinching technology. According to the characteristics of clinching technology, the entire structure of quality monitoring system is proposed. In hardware design, the external hardware circuit of quality monitoring system including of pressure amplifier, power supply, low pass filter, digital channels extended and digital extension isolated circuit is completed based on development platform of ARM9. In software design, the compilation and transplantation Bootloader, the reduction and compilation of Linux kernel, the design of Linux device driver and development of application software with the function of the data collection, data analysis, graphics display and device control are investigated. In quality monitor method design, combining both enveloped curve and window monitoring methods is innovatively introduced and its software realization is discussed.This system which devised with 32 bit microprocessor has many advantages, such as strong function, low consumption, small size and low cost. System is tested in the clinching device of car body laboratory. Running result showed that system had an outstanding capability of monitoring anomalies of clinching process, such as change of sheet metal thickness, change of clinched materials, change of dimensions of clinched tools and clinched tools misalignment etc. And it proves the quality monitoring system design is feasible.